Darren Gilligan (39) was questioned at Blanchardstown Garda station yesterday after his arrest at his home in Corduff Avenue at around 1pm.

Sources say that officers from the local drugs unit recovered a small quantity of heroin described as being worth "a few hundred euro" as well as less than €1,000 in cash during the raid which had been planned for a number of days.

He was questioned under Section 2 of the Drugs Trafficking Act and released without charge last night. A file will be sent to the DPP.

Darren was regularly spotted with his notorious father John before the 62-year-old former gang boss was forced to flee Ireland in March following two attempts on his life.

But unlike his dad, Darren was never considered a major crime figure but he is well known to gardai for drugs and other minor offences.

In October, 2007, Darren was fined €1,100 for possessing €1,000 worth of cocaine.

On that occasion he admitted two charges of possessing cocaine and possession of the drug with intent to supply, at Parlickstown Drive, in Mulhuddart, west Dublin on November 8, 2006, which he had thrown away following a short foot chase by gardai.

The court heard at that time how unemployed Darren was supporting his two children but was no longer with their mother.

He had developed a drug problem while he was in his teens and when the offence occurred he had suffered a relapse and had bought the cocaine for his own personal use.

Darren previously lived in an address at Weston Green in Lucan which has been seized by the Criminal Assets Bureau as part of their massive investigation into his father who was suspected of ordering the murder of crime reporter Veronica Guerin in 1996.

It is understood that after John Gilligan was released from Portlaoise Prison last October, he spent a lot of time with Darren including staying at his son's Blanchardstown home on a number of occasions.

Darren was one of the main revellers at a house party in Clondalkin after the cocky criminal's release last October.

And John was drinking with Darren in the Hole in the Wall pub in the capital's northside when a would-be assassin entered the nearby Halfway House looking for him on the Navan Road armed with a 9mm handgun last December.